The flat panel display technology is developed quickly in recent ten years, and significant progresses are made in the size of screens, display quality and the like. With continuous effort, the performance of all aspects of LCDs has reached the level of the conventional CRT displays, and LCDs are replacing the CRT displays gradually. As the requirement for flat panel displays are increased continuously, the competition among various manufacturers grows increasingly. The manufactures improve the performance of the production continuously while reducing the production cost constantly so as to enhance the competitiveness in market.
By virtue of bendable characteristics, flexible display devices can be applied to many fields requiring curved surface display, such as smart card, electronic paper, smart label, and also to all fields for which the conventional display device can be suitable, and can occupy a huge market share in the future display product market with fantastic beautiful appearance. Presently flexible display devices are the display devices mainly prepared on organic material substrates, such as a cholesteric liquid crystal display, an electrophoresis display, an organic light-emitting display and the like prepared on an organic thin film as polyimide thin film, poly(ethylene 2,6-naphthalate) thin film, poly(ethylene terephthalate) thin film or the like, or the composite thin film thereof.
In preparing a display element on a flexible substrate, it is necessary to make the film layer to be prepared have lower stress, such that the prepared element has flexibility. The conventional equipment for manufacturing display elements always requires the substrate to be kept smooth during the process of preparation, but since relatively great stress occurs in the conventional film layer prepared by magnetron sputtering, the flexible substrate 1 is subjected to be warp deformation after the film layer 2 has been deposited, as shown in FIG. 1. This severely affects the following processes, and even makes a glass substrate break.
Glass material has much better transmittance, chemistry stability, water resistivity and dielectric property than organic materials. Presently, the glass substrate commonly used has a thickness of 0.5-1.1 mm, with the minimum thickness being greater than 0.2 mm. An ultra-thin glass substrate, especially a glass substrate with a thickness less than 0.1 mm, has not only the above properties, but also good flexibility, and is an ideal material for a flexible display substrate. However, since relatively great stress is always generated during the preparation of the conventional film layer, in addition to brittleness of a glass substrate itself, the application of an ultra-thin glass is greatly limited.